How to determine the hardness of water

The most accurate method to determine the hardness of water is to take it to the laboratory for analysis. For example, to the Sanitary and Epidemiological Station. The SES will check not only the concentration of hardness salts, but also record nitrates, pesticides, iron content, hydrogen sulfide, organic impurities and other substances that are often found in groundwater. If you are selecting a water treatment system for a cottage, you need to do a water analysis.

Use test strips to approximate the hardness of the water. They are sold in a pet store or in a store with coffee machines, sometimes in branded home appliance stores. A reagent is applied to the paper, which changes color when in contact with water. The strip is lowered into the water for a while, the intensity of the color will vary depending on the concentration of the substance in the water.

The main disadvantages of this method are low accuracy and the fact that it can be difficult to interpret the test result. We will have to first determine the intensity of the color by eye, comparing it with the "palette" of possible results. And then the numerical values of stiffness indicated on the palette should be converted from European degrees to Russian. High-quality test strips are usually made abroad.

Often, a TDS meter is used to determine the purity and hardness of water. This device, if well calibrated, measures the electrical conductivity of water. And it is affected not only by the concentration of hardness salts, but also by many other parameters, including the temperature of the water and the presence of other impurities in it. The TDS meter will confuse laymen rather than give the right answer in measuring stiffness.